This invention relates to a pedal parking brake of car wheel of a car or the like which operates the parking brake or releases it.
In recent car, a pedal parking brake has been adopted in place of a side brake which operates the parking brake by hand. FIG. 3 shows a conventional pedal parking brake published in an Official Gazette, Patent laid-open No. 63(1988)-106161.
Referring to the organization, a supporting shaft 3 is inserted into a frame 20 of a car body to fix it and a brake arm 4 is supported rotatively to the supporting shaft. A diameter of the supporting shaft 3 is formed so as to be slender stepwise toward a distant direction (right direction in FIG. 3) from the car body frame 20. At a large diameter portion of the car body frame 20, a brake arm cylinder 21 which rotates integrally with the brake arm 4 is inserted outwardly. A coil portion of a lock spring 22 is outwardly provided in a closely contact state so as to be bridged to the brake arm cylinder 21 and the supporting shaft 3. The lock spring 22 consists of a coil spring having a rectangular section, a hook portion 22a of the one end thereof being inserted into the supporting shaft 3, while a hook portion 22b of another end being inserted into a lock releasing ring 23 which is inserted outwardly into the supporting shaft 3 rotatively. When the lock spring 22 rotates the lock releasing ring 23 in a lock releasing direction, the coil portion thereof is adapted to enlarge the diameter.
A rotary drum 15 is outwardly provided at a small diameter portion of the opposite side of the car body frame 20 in the supporting shaft 3, from said rotary drum 15 a brake connecting plate 29 being extended in a brake arm direction 4 whereby the brake connecting plate 29 is connected with the brake arm with a connecting pin 24. Accordingly, when a treading operation of the brake arm 4 is performed, the rotary drum 15 rotates integrally with the brake arm 4 in the same direction thereof.
A fixed drum 14 opposed to the rotary drum 15 is provided at the outside of the rotary drum 15. A connecting plate 25 is fitted with one end surface of the fixed drum 14, and further is connected with the fixed drum cylinder 26 outwardly inserted into the supporting shaft 3 thereby being attached with the supporting shaft 3 indirectly.
Fins 18 and 17 having the teeth form of a comb which extend in the diameter direction of the supporting shaft 3 are attached to the fixed drum 14 and the rotary drum 15 respectively. These fins 18 and 17 are inserted into the fixed drum 14 and the rotary drum 15 respectively and alternately so as to have a fixed clearance, said clearance being filled therein with a viscous material such as a viscous grease or the like. Further, a clutch spring 27 consists of a coil spring having a rectagular section is outwardly provided in a closely contact state to the fixed drum cylinder 26 and the supporting shaft 3 so as to be bridged. The clutch spring 27 is wound in the same direction as the lock spring 22 and outwardly provided to the fixed drum cylinder 26 and the supporting shaft 3 in a closely contact state. The hook portions of these both ends from free ends. Further, the numeral 28 is a holding plate inserted into the top end portion of the supporting shaft 3 so as to prevent slipping out of the fixed drum cylinder 26 and the connecting plate 26 from the top end of the supporting shaft 3. Further, a return spring 5 is provided being bridged between car body frame 20 and brake arm 4.
However, the conventional pedal parking brake described above is complicated in construction. Further, since the lock and the clutch springs are arranged in parallel with respect to the supporting shaft, this device becomes long in the axial direction and to be a large size as a whole.
This invention is performed from such point of view and has its object to provide a pedal parking brake having a compact size.